1. Field of the Invention
This invention relates to a female terminal metal fixture for a connector, which has a box like fitting portion with an open end and is adapted to receive a male terminal metal fixture for a mating connector in the fitting portion.
2. Statement of the Prior Art
For convenience of explanation, a conventional female terminal metal fixture for a connector will be described below by referring to FIG. 3. FIG. 3 is a perspective view of the conventional female terminal metal fixture for a connector.
A female terminal metal fixture 30 in a connecting construction of a connector is produced by punching a metal sheet into a given shape and bending it to a given form. The fixture 30 is provided on its front end with a box like fitting portion 31 having an end opening 34 and on its rear end with a barrel portion 32. An end of an electrical wire not shown is fixed to the barrel portion 32 by means of crimping.
The fitting portion 31 is provided in its interior with an elastic contact piece 33 which is formed by bending inwardly an end of a bottom wall of the portion 31 through the end opening, as shown in FIG. 3. The elastic contact piece 33 is bent slightly upwardly at its middle portion to form a contact area 36. Elasticity is imparted to the elastic contact piece 33 by forming a turned-back portion 35 and the bent contact area 36.
In order to couple a male mating terminal metal fixture not shown to the female terminal metal fixture 30, an elongate projecting tab of the male terminal metal fixture is inserted into the box like fitting portion 31 of the fixture 30. At this time, the tab is clamped between the contact area 36 on the elastic contact piece 33 and an upper wall of the fitting portion by an elastic force exerted in the piece 33, so that the male and female terminal metal fixtures are positively brought into electrical contact with each other.
If the elastic force (contact force) of the elastic contact piece 33 is small, the piece 33 cannot clamp the male terminal metal fixture sufficiently. This results in a contact failure between the male and female terminals. Accordingly, heretofore, inspection of products regarding the contact force of the elastic contact piece has been carried out.
In order to directly measure such contact force, an experiment has been effected by opening a wall of the box like fitting portion 31 to expose the elastic contact piece 33 and then pushing a measuring tool onto the piece 33 to deflect it. However, the measured female terminal metal fixture 30 itself cannot be used as goods. Thus, a measuring tool having a pushing tab which is similar to the tab of the male terminal metal fixture is inserted through the end opening 34 into the fitting portion 31. At this time, the contact force is assumed from a resistance of insertion of the tool.
In a connector to be used in, for example, an electrical circuit for actuating an air bag for a motorcar, an extremely high reliability is required. Thus, the contact area 36 is overlaid with gold to enhance its contact ability. It is required in this kind of female terminal metal fixture to carry out an extremely high quality control such as recording of a history of plating conditions on the contact area 36. One of the methods for observing the plating condition comprises the steps of sampling female terminal metal fixtures in a lot at random, opening an upper wall of the box like fitting portion 31 to expose the contact area 36, and radiating an X-ray on the contact area 36.
There are following problems upon measuring the contact force by the above method. The contact force is not always indicated to be an accurate value by the conventional method which assumes the contact force in accordance with the resistance force of insertion.
Also, in the conventional method of observing the surface condition of the elastic contact piece, the female terminal metal fixture which has been subject to observation cannot be used because the box like fitting portion 31 is opened to expose the elastic contact piece 33.